The Prime Minister has quoted Luke 15:9 to mock Labour's Keir Starmer during an exchange about nuclear power in the House of Commons.
The intervention came during a discussion of energy policy and prices during Prime Minister's Question Time.
Boris Johnson's use of words from the Bible came as he gave a barbed welcome to the Labour leader's support for nuclear energy as a way to reduce dependence on oil and gas. The Prime Minister claimed previous Labour governments had blocked plans to build new nuclear power stations.
"Great news. There is more joy in Heaven over one sinner that repenteth, Mr Speaker, than over a hundred..."
The Prime Minister did not complete the quote but concluded with a claim that previous Labour leaders had opposed nuclear power. "Those were the people, Mr Speaker, who cancelled our nuclear efforts at the time they were in power."
"I'm delighted to welcome them now into the fold."
Keir Starmer rejected the criticism and pointed to delays in current building plans for new nuclear power stations.
"Come off it. Labour is pro-nuclear. This Prime Minister can't get a single brick laid of a new nuclear plant."